A subject that is near and dear to my heart. @Classy Woods, LLC you are absolutely correct! The MTH "-2" steam models used to be everywhere and at reasonable prices but ever since the MTH MW "retirement" they are very hard to find. The number one reason is MTH doesn't make them anymore. I remember when MTH ran the CNJ Blue Comet in PS2. I bought the Queen of the valley but I didn't have enough funds to buy the Blue Comet as well. When MTH ran those engines in Proto 3 I should have bought it and I don't remember why I didn't but my point is now I may never get one because it seems most people that have these engines are holding on to them and the ones that are selling them are selling them at high prices. However, since the pandemic model train prices are up across the board plus the fact that MTH doesn't make the "-2" engines anymore explains why the prices for these engines are high. I live in fear of something catastrophic happening to my MTH train collection because although they may not be worth a ton of money they are NOT easily replaced. i do have on order the Atlas 2-8-0 which is basically a Weaver engine with MTH electronics. This is the closet I can get to a factory MTH -2 engine.
I believe I have around 6 or 7 of these "-2" engines plus about 4 engines that were either converted to 2 rail or are MTH 2 rail from the first time MTH made 2 rail engines in the late '90s. These other engines are not convertible to run on 3 rail track.
Anyway, I have no qualms about running them. If the electronics blow up as Joe mentioned you can get MTH upgrade kits but there is one caveat. If the engine is a Proto 3 and it blows up and you replace the boards with the upgrade kit you may not be able to get the same sound set as what the original Proto 3 board had. Another option is (if you are a 2 rail guy like me and you use DCC) you can install a Blunami (Soundtraxx) or a Loksound decoder or others but those two seem to be two of the most popular options. A pro to going this route is you will get different sounds and more choices for whistles, etc but the downside is you will lose the synchronized smoke and synchronized chuffing. The Bluenami is actually easier to install for 2 rail than the MTH upgrade kit. There are other pros and cons. I am not knowledgeable enough to do a full comparison here. I have been following the 3 rail guys who are installing Bluenami and it is very interesting. I have seen them add smoke but again it will not be synchronized to the chuffs.
My opinion is electronics will always be available in some form or another especially if you use an open protocol like DCC. Hopefully the MTH upgrade kits will also always be available. I don't worry about the electronics. I more worry about other stuff that if it breaks or wears out that is very hard to replace but that goes for any engine in both 2 rail and 3 rail.
